/**
 * Software License, Version 1.0
 * 
 * Copyright 2003 The Trustees of Indiana University. All rights reserved.
 * 
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * 
 * 1) All redistributions of source code must retain the above copyright notice,
 * the list of authors in the original source code, this list of conditions and
 * the disclaimer listed in this license; 2) All redistributions in binary form
 * must reproduce the above copyright notice, this list of conditions and the
 * disclaimer listed in this license in the documentation and/or other materials
 * provided with the distribution; 3) Any documentation included with all
 * redistributions must include the following acknowledgement:
 * 
 * "This product includes software developed by the Community Grids Lab. For
 * further information contact the Community Grids Lab at
 * http://communitygrids.iu.edu/."
 * 
 * Alternatively, this acknowledgement may appear in the software itself, and
 * wherever such third-party acknowledgments normally appear.
 * 
 * 4) The name Indiana University or Community Grids Lab or NaradaBrokering,
 * shall not be used to endorse or promote products derived from this software
 * without prior written permission from Indiana University. For written
 * permission, please contact the Advanced Research and Technology Institute
 * ("ARTI") at 351 West 10th Street, Indianapolis, Indiana 46202. 5) Products
 * derived from this software may not be called NaradaBrokering, nor may Indiana
 * University or Community Grids Lab or NaradaBrokering appear in their name,
 * without prior written permission of ARTI.
 * 
 * 
 * Indiana University provides no reassurances that the source code provided
 * does not infringe the patent or any other intellectual property rights of any
 * other entity. Indiana University disclaims any liability to any recipient for
 * claims brought by any other entity based on infringement of intellectual
 * property rights or otherwise.
 * 
 * LICENSEE UNDERSTANDS THAT SOFTWARE IS PROVIDED "AS IS" FOR WHICH NO
 * WARRANTIES AS TO CAPABILITIES OR ACCURACY ARE MADE. INDIANA UNIVERSITY GIVES
 * NO WARRANTIES AND MAKES NO REPRESENTATION THAT SOFTWARE IS FREE OF
 * INFRINGEMENT OF THIRD PARTY PATENT, COPYRIGHT, OR OTHER PROPRIETARY RIGHTS.
 * INDIANA UNIVERSITY MAKES NO WARRANTIES THAT SOFTWARE IS FREE FROM "BUGS",
 * "VIRUSES", "TROJAN HORSES", "TRAP DOORS", "WORMS", OR OTHER HARMFUL CODE.
 * LICENSEE ASSUMES THE ENTIRE RISK AS TO THE PERFORMANCE OF SOFTWARE AND/OR
 * ASSOCIATED MATERIALS, AND TO THE PERFORMANCE AND VALIDITY OF INFORMATION
 * GENERATED USING SOFTWARE.
 */
package cgl.narada.protocol;

import java.util.ArrayList;
import java.util.LinkedList;

import cgl.narada.matching.rtp.RtpEvent;

/** This is program is written to ensure a considerable degree of concurreny
    in the delivery of events to brokers, and connected entities. Specifically,
    we need to ensure that there is priority in the delivery of events to the
    broker. 

    @author Shrideep Pallickara
    $Date: 2006/05/05 17:32:15 $
    $Revision: 1.5 $
*/

public class EntityEventDispatcher extends Thread {

  private static EntityEventDispatcher instance = new EntityEventDispatcher();
  private boolean waiting = true;
  private LinkedList dispatchUnits;
  private LinkedList audioDispatchUnits;
  private Object syncObject;
  private boolean EntityEventDispatcher_Debug = false;
  private ClientConnectionHandler clientConnectionHandler;
  private boolean isInitialized = false;

  private int pointer;
  private String moduleName = "EntityEventDispatcher: ";


  private EntityEventDispatcher() {
    dispatchUnits = new LinkedList();
    audioDispatchUnits = new LinkedList();
    syncObject = new Object();
    start();
  }

  public void initialize(ClientConnectionHandler clientConnectionHandler) {
    if (clientConnectionHandler != null) {
      this.clientConnectionHandler = clientConnectionHandler;
      isInitialized = true;
    }
  }

  public static EntityEventDispatcher getInstance() {
    return instance;
  }


  public void addDispatchUnit(DispatchUnit dispatchUnit) {
    synchronized (syncObject) {
      if( RtpEvent.isAudioEvent( dispatchUnit.getPayload() ) ){
	audioDispatchUnits.addLast(dispatchUnit);
      }else{
	dispatchUnits.addLast(dispatchUnit);
      }
    }

        
    if (waiting && (dispatchUnits.size() > 0 ||audioDispatchUnits.size() > 0)){
      synchronized(syncObject) {
	syncObject.notify();
      };
    }
  }


  public void run() {
    try { 
      while (true) {
	while(dispatchUnits.size() != 0  || audioDispatchUnits.size() != 0){
	  DispatchUnit dispatchUnit;
	  synchronized (syncObject) {
	    if(audioDispatchUnits.size() != 0){
	      dispatchUnit = (DispatchUnit)audioDispatchUnits.removeFirst();
	    }else{
	      dispatchUnit = (DispatchUnit)dispatchUnits.removeFirst();
	    }
	  }
	  performDispatching(dispatchUnit);
	}
	
	synchronized (syncObject) {
	  waiting = true;
	  syncObject.wait();
	  waiting = false;
	};/*end synchronized(syncObject) */
	
      }/*end of while*/
      
    } catch(Exception e) {
      e.printStackTrace();
    }
  }    
  
  private void performDispatching(DispatchUnit dispatchUnit) {
    byte[] payload = dispatchUnit.getPayload();
    
    if (payload == null) {
      return;
    }

    int ignoreDestination = Integer.MAX_VALUE;
    
    if (dispatchUnit.hasIgnoreDestination() ) {
      ignoreDestination = dispatchUnit.getIgnoreDestination();
    }
   


    if (dispatchUnit.hasArrayListDestinations()) {
      ArrayList destinations = dispatchUnit.getArrayListDestinations();
      if (destinations == null) {
	return;
      }
      sendToClientNodes(payload, destinations, ignoreDestination);
    }
    
  }



   /** This method provides for routing information to clients that are
       connected to the server node. Given a list of clients to which data
       needs to be routed to, this method routes data to each client conatined
       within the encapsulated destination list.
       @param data The data that needs to be routed.
       @param destination The list of clients to which this information needs
       to be routed.
   */
  private void sendToClientNodes(byte[] data, ArrayList destinations,
				 int ignoreDestination) {
    Integer ignoreKey = new Integer(ignoreDestination);
    if (EntityEventDispatcher_Debug) {
      System.out.println(moduleName + "Will route to " + destinations);
      System.out.println(moduleName + "Need to ignore destination " +
			 ignoreKey);
    }
    
    
    if (pointer >= destinations.size()){
      pointer = 0;
    }
    
    //first route to clients whose index is more than pointer
    for (int i = 0; i < destinations.size(); i++) {
      Integer clientKey = (Integer)destinations.get(i);
      if (clientKey.equals(ignoreKey) ) {
	/*System.out.println(moduleName + "Ignoring destination [" + clientKey 
	  + "]"); */
	continue;
      } /** Ignore the specified destination */
      clientConnectionHandler.routePayloadToEntity(clientKey, data);
    }
    
  } 
}
